Hand sander



A. J. DREMEL.

Feb. 12, 1952 HAND SANDER 2 SHEETS SHEET 1 Filed Dec. 4, 1947 INVENTOR ALBERT J. DREMEL ATTORNEYS Feb. 12, 1952 J, DREMEL 2,585,637

HAND SANDER Filed Dec. 4, 1947 2 SHEETSSHEET 2 lNVENTOR ALBERT JDREMEL ATTORNEYS Patented Feb. 12, 1952 UNITED STATES PATENT OFFICE HAND SANDER- Albert J. Dremel, Racine, Wis.

ApplicationDecember 4, 1947, Serial No. 789,692"

' 6 Claims. I

This invention appertains to electrically operated, portable tools of the hand sander type and 'is an improvement over my prior Patent No.

2,324,292 issuedto me July 13, 1943.

One of the primary objects of my present invention is to provide novel means for resiliently supporting the sander block from the frame, so that the desired reciprocatory action of the sander block will be had without objectionable outward thrust.

' Another salient object of my invention is the provision of novel means for adjusting the active stroke of the armatures and the supporting springs, so as. to effectively govern the action of the block.

A further important object of my invention is to provide novel means for resiliently supporting objectionable clicking noises of the armatures contacting the magnets.

A still further object of my invention is the provision of adjusting blocks disposed in the arcuate connecting portions of the supporting springs with means for simultaneously and syn-- chronously adjusting said blocks by the operation 'of a single control member:

A still further important object 01' my" invenparts wherebya durableand efficient device will be had, which can be manufactured at a reasonable cost.

With the above and other objects in view, which will appearas the description proceeds, the invention resides in: the novel" construction, com-- bination and arrangement Of' partssubstantially as hereinafter described; and more particularly defined" by the" appended claims; It beingundertion is the provision of" a novel assemblage of stood; that such changes in the precise embodimentsof the herein disclosed invention may be made as come within the scope of the claims.

In the accompanyingdrawings' is illustrated a complete example of the disclosed embodiments of the present invention constructed-according to the-best mode so far devised-for the practical application of 'theprinciplesthereofi In the-drawings: Figure 1 is a central, vertical, sectional view "through my-mexnbered handsander, the section 1 2 being taken on the line l-l of Figure 2 looking in the direction of the arrows.

Figure 2 is a horizontal, sectional view through the complete sander taken on the line 2-4" of Figure 1 looking in the direction of the arrows.

Figure 3 is a section similar to Figure 2, but taken on the line 3-3 of Figure L'lookin'g in the direction of the arrows, the view illustrating, more particularly, the connection of the handle with the casing and supporting plate and its connections with the casing.

Figure 4 is a transverse, sectional view through the hand sander taken on the 1ine44' of Figure 1 looking in the direction of the arrows.

Figure 5 is a fragmentary detail, sectional view taken on the line 5-5 of Figure 1 looking. in the direction of the arrows, illustrating'the' means employed for adjusting one of the bumper blocks in a supporting spring.

Referring to the drawings in detail, wherein similar reference characters designate corresponding parts throughout the several views, the letter S generally indicates my improved hand sander, and the same includes a casing 6 open at its lower end. The casing 6 can be formed from any desired material, and the same'is preferably, but not necessarily, in the nature of a casting. As illustrated the casing 6 includes front and rear curved end walls 1' and 8 and connecting" side walls 9 and I01 The end walls 7 and 8' carry inwardly directed ears I l and I2 adjacent to their-upper en'ds fora purpose which will later appear.

The top of the casing 6 is closed by a manipulating hand grip I3 formed from electric insulating material. Suitable fastenin'g'elements I4 ext'endithrough the sides of'the hand grip |3- into.

the casing 6 for holding the hand grip in proper position.

Mounted below the casing B is the" sanding member l5. The sanding member 15' includes a carrier plate i6, the opposite" ends ofv which canbe upturned to provide flanges H The abrasive material, such as-a' sheet o'f-sand paper or cloth l8, is placed under the platewith the ends thereof over the flanges 11. Means [9' is providedfor deta'chably engaging the ends of the abrasive strip to holdthe same'in' position. This means l'9 forms th'esubject matter of a separate application for patent and will not be described in detail here. A cushioning pad; suchas a piece of felt 2D, is placed between thet-alirasive-strip' I8 and the-carrier platesl'fii.

In order to'bring about the correct-reciprocation of the sandingm'ember I5; I provideone or moie altemating electm-magnets'lli mthe present showing, I have illustrated two such magnets, and each magnet is of identical construction. Each magnet is provided with an armature 22, and each electro-magnet can be of the same character as shown in my Patent No. 2,233,862 issued March 4, 1941. Each magnet includes an E-shaped core 23 formed by a plurality of laminations. A conventional winding 24 is provided for the magnet and can be protected by a suitable cover. Certain laminations, indicated by the reference character 25, of each core 23 extend above the body of the core and these laminations are arranged in spaced parallel relation and have formed on their upper ends laterally extending cars 26. The ears 26 of each magnet 2| are secured by suitable fastening elements 2! to a supporting plate 28. This plate 28 is in turn fastened to the ears II and I2 of the casing by removable fastening elements such as screws 29. The supporting plate 28, in effect, divides the casing into an upper compartment for a certain switch mechanism 39 and a lower compartment for the magnets and their armatures. Each armature 22 is rigidly secured to the lower end of a leaf spring 3|. Each leaf spring 3| is provided at its upper end with a substantially right angularly extending attaching foot 32, and the attaching foot 32 is placed between the ears 26 and the supporting plate 28 and is securely held 30 in position by the fastening elements 21 employed for the magnets. Each leaf spring has an intermediate arcuate connecting flexing portion 33, and the springs 33 normally function to draw the armatures 22 away from the electromagnets 2|. A leaf spring 34 is secured to and depends from each armature 22, and. the flexing spring 3| and the springs 34 are similar in construction, and the springs 34, in fact, could constitute continuations of the springs 3|, if such should be desired. The lower ends of the springs 34 terminate in substantially right angularly extending attaching feet 35 which are firmly secured to the plate |6 of the sanding element or member I5.

Attention is directed to the position of the electro-magnets relative to their armatures 22, and this feature and advantages thereof have been fully set forth and claimed in my prior Patent No. 2,324,292 heretofore mentioned.

Extending into the handle, preferably from the rear end thereof, are the electric conducting wires 36 for the electro-magnets, and the switch mechanism 30 is employed for opening and closing the circuit to the magnets.

As brought out in the objects of the application, one of the main features of the invention is to provide means for regulating the stroke of the armatures 22 and to prevent the armatures from coming into direct contact with the electro-magnets, so that all objectionable click- -ing noise will be eliminated. This means includes an adjusting block 31 for each spring 3|,

and the blocks are fitted in the arcuate connecting portions 33 of the springs 3|. The forward faces of the adjusting blocks 3| are curved as at 38 to conform to the configuration of the arcuate connecting portions 33. The blocks 31 are arranged adjacent to the lower portions of the aligned slots 39, and these slots slidably receive :wedge shaped keys 40.

Hence, the keys 40 are also guided in their movement by their laminations 25. The lower faces of the keys engage and ride on the upper edges of the adduatin: blocks 31. The upper faces of the blocks can be inclined to agree with the inclination of the wedge keys as is clearly shown in Figure 5. Ob viously, when the wedge keys 40 are moved inwardly, the wedge blocks 31 will be moved down wardly against the curved portions 33 of the springs 3| and will limit the inward movement of the springs 3| and the armatures 22 toward the magnets 2|. In fact, the blocks are preferably set, so that the armatures will have a movement just short of contact with the magnets.

Means is provided for synchronously and simultaneously adjusting the keys, and this means includes an operating plate 4| which extends longitudinally of the casing 6. The outer ends of the keys 4|] are rigidly secured to the plate 4| so that the keys 40 and the plate 4| move together as a single element. The keys can have wound about the same, expansion springs. 42. These springs bear respectively against certain of the laminations 25 and against the plate 4| and function to normally urge the plate 4| laterally away from the magnets, so as to pull the narrow ends of the keys toward the adjusting blocks 31.

Extending through the laminations 25 of the forward magnet 2| is a bolt 43 and this bolt extends through the adjusting plate 4|. Threaded upon the outer end of the bolt is a nut 44 having a suitable finger piece 45. The nut bears against the plate 4| and by turning the nut in the proper direction, the plate 4| can be forced inwardly against the tension of the springs 42 for moving the keys 40 inwardly so that the blocks 31 can be forced down.

While I have specifically described my invention applied to a sander, it is to be understood that the plans of my invention can be utilized in other electrical tools embodying a movable operating member.

What I claim as new is:

1. In an electrically operated tool, a support, an alternating electro-magnet carried by the support, said magnet including a core and laminations, certain of said laminations being extended above the core and other laminations, an armature within the field of the electro-magnet, a leaf spring connecting the armature to the support including an intermediate arcuate connecting flexing portion, an adjusting block disposed between and guided by the extended laminations engaging the arcuate intermediate connecting portion of the spring, and means for varying the position of the block in said arcuate connecting portion of the spring.

2. In an electrically operated tool, a support, an alternating electro-magnet carried by the support, said magnet including a core and laminations, certain of said laminations being extended above the core and other laminations, an armature within the field of the eleotro-magnet, a leaf spring connecting the armature to the support including an intermediate arcuate connecting portion, an adjusting block disposed between and guided by the extended laminations engaging the arcuate intermediate connecting portion of the spring, and means for varying the position of the block in said arcuate connecting ing member arranged below said casing, an electro-magnet arranged in the casing, means securing the electro-magnet to the casing, an armature for the electro-magnet and disposed within the field thereof, a leaf spring connecting the armature to the casing, and a leaf spring connecting the first mentioned spring and armature to the sanding member.

4. In an electrically operated tool, a support, an electro-magnet carried by the support, said magnet including a core and laminations, certain of said laminations being extended above the core and the other laminations, an armature arranged within the magnetic field of the electro-magnet, a leaf spring connecting the armature to the support including an intermediate arcuate flexing connecting portion, an adjusting block disposed between and guided by the extended laminations engaging the connecting portion, and means for varying the position of the block in said connecting portion including a wedge key extending transversely through the extended laminations engaging the said block, spring means normally urging the wedge key in a direction away from the block, a carrier plate secured to the wedge key, and means for adjusting and holding the carrier plate and wedge key against the tension of said spring.

5. In an electrically operated device, a casing, a movable plate arranged below the casing, an

electro-magnet secured in the casing, an armature in the casing for the electro-magnet disposed within the field of the electro-magnet, a spring in the casing having substantially parallel disposed attaching feet at its opposite ends, means securing the feet respective to the casing and the plate, and means securing the armature to an intermediate portion of the spring between the attaching feet.

6. In an electrically operated device as defined in claim 5, and said spring having arcuate flexing portions adjacent to the feet.

ALBERT J. DREMIEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

